The aims of this study are: 1) to investigate the occurrence and nature of children's suicidal thoughts and gestures; 2) to study the related factors in maternal diagnostic characteristics, and 3) to compare the clinical, developmental, demographic, age, and gender characteristics of suicidal and non-suicidal children. In a longitudinal study, 115 biological sibling pairs from three maternal diagnostic categories, Controls, Unipolars, Bipolars, were seen at three times across six years. Assessments of mothers were made from psychiatric interviews (SADS-L, RDC Criteria); assessments of children's were made using psychiatric interviews (CAS at Times I and II and DICA at Time 3). Among older siblings at Time III, ratings were significantly different overall (p is less than .03; between control vs. bipolar groups, ratings of bipolar offspring were significantly higher (p is less than .05). Suicidal behavior in offspring was found to relate to maternal psychopathology and child's age, but not gender.